MMVD stands for Myxomatous Mitral Valve Disease, also known as degenerative mitral valve disease.
The exact cause of MMVD is still unknown, but we do know that it commonly affects small to medium breed dogs. Certain breeds, such as Cavalier King Charles spaniels, Dachshunds, and Chihuahuas, can develop MMVD at a younger age, suggesting a genetic component.
In MMVD, the mitral valve, which acts like a door in the heart, becomes thickened and loses its function. This leads to blood leaking back from the left ventricle into the left atrium because the “door” isn’t closing tightly. The severity of the condition depends on how much blood leaks and whether it causes the left heart chambers to enlarge. A cardiologist evaluates MMVD and categorizes it into five stages: A, B1, B2, C, and D.
When a dog’s heart chambers are enlarged, medication is prescribed. The medication(s) can delay the progression of the disease but does not cure it. Some dogs have a slow progression while some dogs deteriorate rapidly. In humans, MMVD often requires surgery for a cure. However, surgery in dogs is complex and super expensive, and it’s only available in certain countries like Japan and the UK.
In recent years, a minimally invasive trans-catheter technique (using V-clamp by Hongyu Medical, China) has become available. This procedure involves a small incision on the chest and clamping the parts of the mitral valve that are causing the leakage. It’s less expensive (about one-third to one-fourth of the cost of open-heart surgery) and can be performed within about 1 hour or less without stopping the heart or using a cardio-pulmonary bypass machine.
The V-clamp surgery has both advantages and limitations. With decreased leakage and improvement in heart function, the dogs may require fewer or lower doses of cardiac medications, which can reduce the burden of long-term medication management and fee. Discontinuation of cardiac medications may also be possible.
However, for a few months after the surgery, the dogs have to take a blood thinner to prevent blood clot formation. Besides, not all dogs are suitable for the procedure and some may respond differently to the V-clamp surgery. Factors such as body size and mitral valve/annular pathology, along with other concurrent diseases, may disqualify the dog from undergoing the procedure.
At present, countries such as South Korea, the UK, and Thailand have reported a good success rate in dogs which underwent the procedure.
Recently, the Shinzō team underwent training on V-clamp surgery in Shanghai, China. We are determined to kickstart this V-clamp surgery in Malaysia, hoping that by offering it, we can improve the quality of life and survival rates for dogs with advanced MMVD.
